Laboratory shield



FIG. 1 is a front elevational view of a laboratory shield, showing my new design;

FIG. 2 is a side elevational view of the device shown in FIG. 1 as viewed from the right hand side.

FIG. 3 is a rear elevational view of the device shown in FIG. 1 and FIG. 2; and

FIG. 4 is a top plan view of FIG. 3. 

The ornamental design for a laboratory shield, as shown. 